package org.hibernate.dialect;

import java.sql.SQLException;
import java.sql.Types;

import org.hibernate.JDBCException;
import org.hibernate.boot.TempTableDdlTransactionHandling;
import org.hibernate.dialect.function.*;
import org.hibernate.dialect.identity.*;
import org.hibernate.dialect.pagination.*;
import org.hibernate.dialect.unique.SqliteUniqueDelegate;
import org.hibernate.dialect.unique.UniqueDelegate;
import org.hibernate.engine.spi.RowSelection;
import org.hibernate.exception.*;
import org.hibernate.exception.spi.*;
import org.hibernate.hql.spi.id.IdTableSupportStandardImpl;
import org.hibernate.hql.spi.id.MultiTableBulkIdStrategy;
import org.hibernate.hql.spi.id.local.AfterUseAction;
import org.hibernate.hql.spi.id.local.LocalTemporaryTableBulkIdStrategy;
import org.hibernate.internal.util.JdbcExceptionHelper;
import org.hibernate.type.StandardBasicTypes;

public class SqliteDialect extends Dialect {
	private final UniqueDelegate uniqueDelegate;
	
	private static final LimitHandler LIMIT_HANDLER = new AbstractLimitHandler() {
		@Override
		public String processSql(String sql, RowSelection selection) {
			final boolean hasOffset = LimitHelper.hasFirstRow( selection );
			return sql + (hasOffset ? " limit ? offset ?" : " limit ?");
		}

		@Override
		public boolean supportsLimit() {
			return true;
		}

		@Override
		public boolean bindLimitParametersInReverseOrder() {
			return true;
		}
	};
	
	/**
	 * Constructs a SQLiteDialect
	 */
	public SqliteDialect() {
		registerColumnType(Types.BIT, "boolean");
		// registerColumnType(Types.FLOAT, "float");
		// registerColumnType(Types.DOUBLE, "double");
		registerColumnType(Types.DECIMAL, "decimal");
		registerColumnType(Types.CHAR, "char");
		registerColumnType(Types.LONGVARCHAR, "longvarchar");
		registerColumnType(Types.TIMESTAMP, "datetime");
		registerColumnType(Types.BINARY, "blob");
		registerColumnType(Types.VARBINARY, "blob");
		registerColumnType(Types.LONGVARBINARY, "blob");

		registerFunction("concat", new VarArgsSQLFunction(StandardBasicTypes.STRING, "", "||", ""));
		registerFunction("mod", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "?1 % ?2"));
		registerFunction("quote", new StandardSQLFunction("quote", StandardBasicTypes.STRING));
		registerFunction("random", new NoArgSQLFunction("random", StandardBasicTypes.INTEGER));
		registerFunction("round", new StandardSQLFunction("round"));
		registerFunction("substr", new StandardSQLFunction("substr", StandardBasicTypes.STRING));
		registerFunction("trim", new AbstractAnsiTrimEmulationFunction() {
			@Override
			protected SQLFunction resolveBothSpaceTrimFunction() {
				return new SQLFunctionTemplate(StandardBasicTypes.STRING, "trim(?1)");
			}

			@Override
			protected SQLFunction resolveBothSpaceTrimFromFunction() {
				return new SQLFunctionTemplate(StandardBasicTypes.STRING, "trim(?2)");
			}

			@Override
			protected SQLFunction resolveLeadingSpaceTrimFunction() {
				return new SQLFunctionTemplate(StandardBasicTypes.STRING, "ltrim(?1)");
			}

			@Override
			protected SQLFunction resolveTrailingSpaceTrimFunction() {
				return new SQLFunctionTemplate(StandardBasicTypes.STRING, "rtrim(?1)");
			}

			@Override
			protected SQLFunction resolveBothTrimFunction() {
				return new SQLFunctionTemplate(StandardBasicTypes.STRING, "trim(?1, ?2)");
			}

			@Override
			protected SQLFunction resolveLeadingTrimFunction() {
				return new SQLFunctionTemplate(StandardBasicTypes.STRING, "ltrim(?1, ?2)");
			}

			@Override
			protected SQLFunction resolveTrailingTrimFunction() {
				return new SQLFunctionTemplate(StandardBasicTypes.STRING, "rtrim(?1, ?2)");
			}
		});
		uniqueDelegate = new SqliteUniqueDelegate(this);
	}

	@Override
	public IdentityColumnSupport getIdentityColumnSupport() {
		return new SqliteIdentityColumnSupport();
	}
	
	@Override
	public boolean supportsLockTimeouts() {
		return false;
	}

	@Override
	public String getForUpdateString() {
		return "";
	}

	@Override
	public boolean supportsOuterJoinForUpdate() {
		return false;
	}
	
	@Override
	public boolean supportsCurrentTimestampSelection() {
		return true;
	}

	@Override
	public boolean isCurrentTimestampSelectStringCallable() {
		return false;
	}

	@Override
	public String getCurrentTimestampSelectString() {
		return "select current_timestamp";
	}
	
	@Override
	public MultiTableBulkIdStrategy getDefaultMultiTableBulkIdStrategy() {
		return new LocalTemporaryTableBulkIdStrategy(
				new IdTableSupportStandardImpl() {
					@Override
					public String getCreateIdTableCommand() {
						return "create temporary table if not exists";
					}

					@Override
					public String getDropIdTableCommand() {
						return "drop temporary table";
					}
				},
				AfterUseAction.DROP,
				TempTableDdlTransactionHandling.NONE
		);
	}
	
	private static final int SQLITE_BUSY = 5;
	private static final int SQLITE_LOCKED = 6;
	private static final int SQLITE_IOERR = 10;
	private static final int SQLITE_CORRUPT = 11;
	private static final int SQLITE_NOTFOUND = 12;
	private static final int SQLITE_FULL = 13;
	private static final int SQLITE_CANTOPEN = 14;
	private static final int SQLITE_PROTOCOL = 15;
	private static final int SQLITE_TOOBIG = 18;
	private static final int SQLITE_CONSTRAINT = 19;
	private static final int SQLITE_MISMATCH = 20;
	private static final int SQLITE_NOTADB = 26;

	@Override
	public SQLExceptionConversionDelegate buildSQLExceptionConversionDelegate() {
		return new SQLExceptionConversionDelegate() {
			@Override
			public JDBCException convert(SQLException sqlException, String message, String sql) {
				final int errorCode = JdbcExceptionHelper.extractErrorCode( sqlException ) & 0xFF;
				if (errorCode == SQLITE_TOOBIG || errorCode == SQLITE_MISMATCH) {
					return new DataException( message, sqlException, sql );
				}
				else if (errorCode == SQLITE_BUSY || errorCode == SQLITE_LOCKED) {
					return new LockAcquisitionException( message, sqlException, sql );
				}
				else if ((errorCode >= SQLITE_IOERR && errorCode <= SQLITE_PROTOCOL) || errorCode == SQLITE_NOTADB) {
					return new JDBCConnectionException( message, sqlException, sql );
				}

				// returning null allows other delegates to operate
				return null;
			}
		};
	}

	@Override
	public ViolatedConstraintNameExtracter getViolatedConstraintNameExtracter() {
		return new TemplatedViolatedConstraintNameExtracter() {
			@Override
			protected String doExtractConstraintName(SQLException sqle) throws NumberFormatException {
				final int errorCode = JdbcExceptionHelper.extractErrorCode( sqle ) & 0xFF;
				if (errorCode == SQLITE_CONSTRAINT) {
					return extractUsingTemplate( "constraint ", " failed", sqle.getMessage() );
				}
				return null;
			}
		};
	}

	@Override
	public boolean supportsUnionAll() {
		return true;
	}
	
	@Override
	public boolean canCreateSchema() {
		return false;
	}

	@Override
	public boolean hasAlterTable() {
		// As specified in NHibernate dialect
		return false;
	}

	@Override
	public boolean dropConstraints() {
		return false;
	}

	@Override
	public boolean qualifyIndexName() {
		return false;
	}

	@Override
	public String getAddColumnString() {
		return "add column";
	}

	@Override
	public String getDropForeignKeyString() {
		throw new UnsupportedOperationException( "No drop foreign key syntax supported by SQLiteDialect" );
	}

	@Override
	public String getAddForeignKeyConstraintString(String constraintName,
			String[] foreignKey, String referencedTable, String[] primaryKey,
			boolean referencesPrimaryKey) {
		throw new UnsupportedOperationException( "No add foreign key syntax supported by SQLiteDialect" );
	}

	@Override
	public String getAddPrimaryKeyConstraintString(String constraintName) {
		throw new UnsupportedOperationException( "No add primary key syntax supported by SQLiteDialect" );
	}

	@Override
	public boolean supportsCommentOn() {
		return true;
	}

	@Override
	public boolean supportsIfExistsBeforeTableName() {
		return true;
	}
	
	@Override
	public boolean doesReadCommittedCauseWritersToBlockReaders() {
		return true;
	}

	@Override
	public boolean doesRepeatableReadCauseReadersToBlockWriters() {
		return true;
	}

	@Override
	public boolean supportsTupleDistinctCounts() {
		return false;
	}
	
	@Override
	public int getInExpressionCountLimit() {
		return 1000;
	}
	
	@Override
	public UniqueDelegate getUniqueDelegate() {
		return uniqueDelegate;
	}
}
